What make us human?

     During school when the teacher ask to student what are different between Human and Chimpanzees.Some student will answer " Teacher, Chimpanzees did not have brain but Human have", which means human can think but chimpanzees can't. Some student may answer " Chimpanzees can't speak English but human can", and also students may also answer " Human can finish up your homework but chimpanzees never finish it". And some naughty voice interrupted, " If you did not finish your homework you are chimpanzees in human skin.(hahahaha).The very simple answer can bring to very deep explanation about this difference genetically. So how?


For your information, Humans are distinct from chimpanzees in a number of important respects, despite sharing nearly 99 percent of their DNA (which means their DNA 99% homology and only 1% difference. What are so significance of 1 % difference to produce very difference species using the idea of ability to think.


1% of difference can also give very big change in DNA. 1 % of  3 billions of letters that build human genome which means they differ in about 15 million letter. What are so interesting is the in 1 % difference, on some sequence involve in the brain formation which is gene HAR1 and ASPM. Another  genes are FOXP2 (involve in oral communinacation), AMY1,LCT and HAR2( capability to do work).


HAR1, Active in the brain; may be necessary for development of the cerebral cortex, which is especially large in humans(involve overlapping genes). Possibly also involved in sperm production. ASPM controls brain size, which has more than tripled over the course of human evolution.Both genes increase the complexity of human brain compare to chimpanzees.

FOXP2, facilitates formation of words by the mouth, enabling modern human speech. Its role in speech was discovered by researchers at the University of Oxford in England, who reported in 2001 that people with mutations in the gene are unable to make certain subtle, high-speed facial movements needed for normal human speech, even though they possess the cognitive ability to process language.

AMY1,Facilitates digestion of starch, which may have enabled early humans to exploit novel foods. Changes in the gene AMY1, which encodes salivary amylase, an enzyme involved in digesting starch, constitute one well-known adaptation of this kind. The mammalian genome contains multiple copies of this gene, with the number of copies varying between species and even between individual humans. But overall, compared with other primates, humans have an especially large number of AMY1 copies. In 2007 geneticists at Arizona State University showed that individuals carrying more copies of AMY1 have more amylase in their saliva, thereby allowing them to digest more starch. The evolution of AMY1 thus appears to involve both the number of copies of the gene and the specific changes in its DNA sequence.




The gene for lactase (LCT), an enzyme that allows mammals to digest the carbohydrate lactose, also known as milk sugar. In most species, only nursing infants can process lactose. But around 9,000 years ago—very recently,in evolutionary terms—changes in the human genome produced versions of LCT that allowed adults to digest lactose. Modified LCT evolved independently in European and African populations, enabling carriers to digest milk from domesticated animals. Today adult descendants of these ancient herders are much more likely to tolerate lactose in their diets than are adults from other parts of the world, including Asia and Latin America, many of whom are lactose-intolerant as a result of having the ancestral primate version of the gene.


HAR2, Drives gene activity in the wrist and thumb during development,an activity that may have given the hand enough dexterity to make and use complex tools. In more detail, HAR2, a gene regulatory region and the second most accelerated site on my list, is a case in point. In 2008 researchers at Lawrence Berkeley National Laboratory showed that specific base differences in the human version of HAR2 (also known as HACNS1), relative to the version in nonhuman primates, allow this DNA sequence to drive gene activity in the wrist and thumb during fetal development, whereas the ancestral version in other primates cannot. This finding is particularly provocative because it could underpin morphological changes in the human hand that permitted the dexterity needed to manufacture and use complex tools. This gene involve the novel physical structure in human that only organism has opposing thumb, thus can create tools or operates machine or do works.

As conclusions, the 1 % difference between human and chimpanzees give human ability to think,(because of complexity of the brain structure compare to chimp), to speak, to has innovation in making tools and operates machine and also the advance in digestive system.